It is difficult to supply power from the main power supply of a motor vehicle to an electric component or sub-assembly that is arranged within a rotating body of the vehicle (e.g., a wheel, tire, or rim of the vehicle). Accordingly, technologies, including, for example, tire pressure monitoring systems (TPMS), active road profile analysis systems, tire wear indicators, active air compression devices, and/or acceleration sensors, generally require a localized energy source to operate. Such technologies have been traditionally powered, for example, via batteries that are internal to the wheel/tire assembly. Size and weight constraints, however, generally limit the size and/or number of the batteries that may be used, and the subsequent amount of power that can be supplied by the batteries to the sub-assemblies. Furthermore, batteries have a finite life and will eventually need to be replaced, which generates waste and may be difficult and/or expensive.
It may, therefore, be advantageous to provide a localized energy source (i.e., internal to the wheel/tire assembly) that may generate power for such electric sub-assemblies. Various energy harvesting mechanisms have been developed that may convert mechanical energy to electrical energy via, for example, piezoelectric, electromagnetic, or electrode/dielectric devices. Such energy harvesting mechanisms, however, are generally limited in their power generation (e.g., by the mechanical forces that can be captured) and their structural design. Piezoelectric technologies, for example, generally use a cantilever beam energy harvesting device, which is limited to capturing a bending stress of the beam as the tire rotates. Electrode/dielectric technologies may include stretchable energy harvesting devices that are attached to a side face of the interior of the tire, and which are limited to specific geometries that are smaller than a contact patch of the tire with the road, in order to capture a strain occurring in the tire.
It may, therefore, be advantageous to provide an energy harvesting mechanism within the wheel/tire assembly that can utilize a broad range of mechanical forces and displacements to generate a large range of electrical currents and voltages. It may also be advantageous to provide an energy harvesting mechanism within the wheel/tire assembly that may have various configurations and/or geometries to provide both design flexibility and power maximization. It may be further advantageous to provide systems and methods for generating power that utilize such energy harvesting mechanisms to power sub-assemblies mounted on a tire of the vehicle.